The conventional circuit breaker uses a fuse between the switch and the circuit such that when there is an electrical overload, the fuse will first melt before the overload causes damages. However, if the fuse is not properly installed or an improper fuse is used the overload current cannot melt the fuse and a disaster can be caused. U.S. Pat. Nos. 5,262,748, 4,167,720, 4,937,548, 5,223,813, 5,451,729, and 5,558,211 disclose different types of circuit breakers which commonly include a complicated mechanism to drive the bimetallic plate which is expected to be deformed and bent when there is overload in current. Nevertheless, it is noted that the bimetallic plate may not be completely deformed as desired because it is not possible to be freely deformed when the overload current occurs, and the bimetallic plate is still in contact with the terminal to generate sparks and therefore cause disaster.
Therefore, it is desired to have a protection mechanism for a switch device that includes a pivotable member with a shorter tongue and the pivotable member is pivoted an angle when the switch device is in “ON” position and the bimetallic plate is deformed upward and not stopped by the shorter tongue.